Image capturing apparatus

ABSTRACT

An image capturing apparatus comprises: an image sensor adapted to opto-electronically convert the image of a subject; an optical member placed in front of the image sensor; first and second piezoelectric elements placed at respective ones of both ends of the optical member; first and second driving units adapted to independently vibrate the first and second piezoelectric elements, respectively; a detection unit having first and second detecting piezoelectric elements placed adjacent to the first and second piezoelectric elements, respectively, for detecting vibration of the optical member; and a first control unit adapted to control the first and second driving units and the detection unit so as to vibrate the optical member by vibrating the first piezoelectric element and detect vibration of the optical member using the second detecting piezoelectric element, or vibrate the optical member by vibrating the second piezoelectric element and detect vibration of the optical member using the first detecting piezoelectric element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique for removing a foreignsubstance that has attached itself to the surface of an optical elementplaced in front of an image sensor in an image capturing apparatus suchas a digital camera.

2. Description of the Related Art

Many types of electronic image capturing apparatus (referred to simplyas a “camera” below) typified by a digital still camera or video camerahave become widespread rapidly owing to their immediacy and highaffinity for personal computers. Such cameras obtain image data byopto-electronically converting the image of a subject using an imagesensor and comprise generally small components such as the image sensor,a shooting optical system and an optical element such as a low-passfilter placed in front of the image sensor.

If a foreign substance such as dust attaches itself to, say, the opticalelement in the camera, the foreign substance itself appears in the imageand causes a decline in the quality of the image. For this reason,various techniques for removing an adhering foreign substance byvibrating the optical element have been proposed and have started to beput into practice in recent years (see the specification of JapanesePatent Application Laid-Open No. 2003-333391).

In a case where an adhering foreign substance is removed by vibrating anoptical element as described above, a vibrating device using apiezoelectric element generally is employed as the device that vibratesthe optical element. For example, in a case where the vibrating deviceusing a piezoelectric element malfunctions for some reason, there is thepossibility that the vibration applied to the optical element willbecome too large and that this will destroy the optical element.

If the optical element is destroyed, it will be necessary to check theimage by performing a shooting operation in order to detect suchdestruction. The problem which arises is that unnecessary labor isimposed upon the user.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the above-describedcircumstances and seeks to so arrange it that detection of anabnormality in a vibrating device that employs a piezoelectric elementcan be readily achieved with a simple arrangement.

According to a first aspect of the present invention, the foregoingobject is attained by providing an image capturing apparatus comprising:an image sensor adapted to opto-electronically convert the image of asubject; an optical member placed in front of the image sensor; firstand second piezoelectric elements placed at respective ones of both endsof the optical member; first and second driving units adapted toindependently vibrate the first and second piezoelectric elements,respectively; a detection unit having first and second detectingpiezoelectric elements placed adjacent to the first and secondpiezoelectric elements, respectively, for detecting vibration of theoptical member; and a first control unit adapted to control the firstand second driving units and the detection unit so as to vibrate theoptical member by vibrating the first piezoelectric element and detectvibration of the optical member using the second detecting piezoelectricelement, or vibrate the optical member by vibrating the secondpiezoelectric element and detect vibration of the optical member usingthe first detecting piezoelectric element.

According to a second aspect of the present invention, the foregoingobject is attained by providing an image capturing apparatus comprising:an image sensor adapted to opto-electronically convert the image of asubject; an optical member placed in front of the image sensor; firstand second piezoelectric elements placed at respective ones of both endsof the optical member; first and second driving units adapted toindependently vibrate the first and second piezoelectric elements,respectively; a first detection unit connected between the firstpiezoelectric element and the first driving unit and adapted to detectan output signal that is output from the first piezoelectric elementowing to vibration of the first piezoelectric element; a seconddetection unit connected between the second piezoelectric element andthe second driving unit and adapted to detect an output signal that isoutput from the second piezoelectric element owing to vibration of thesecond piezoelectric element; and a first control unit adapted tovibrate the optical member by vibrating the first piezoelectric elementand detect the output signal, which is output from the secondpiezoelectric element, using the second detection unit, or vibrate theoptical member by vibrating the second piezoelectric element and detectthe output signal, which is output from the first piezoelectric element,using the first detection unit.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a single-lens reflex digital cameraaccording to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating the external appearance of thesingle-lens reflex digital camera of the first embodiment;

FIG. 3 is an enlarged view, as seen from above, of the vicinity of animage sensor shown in FIG. 1;

FIG. 4 is a diagram illustrating a portion of an optical member in FIG.3 as seen from the side of the image sensor, as well as the peripheralcircuits of piezoelectric elements;

FIG. 5 is a block diagram illustrating the configuration of a controlcircuit for controlling piezoelectric elements and detectingpiezoelectric elements;

FIGS. 6A and 6B are flowcharts illustrating operation relating tocontrol of vibration of an optical member by a camera controller;

FIG. 7 is a diagram illustrating a portion of an optical member in FIG.3 as seen from the side of the image sensor, as well as the peripheralcircuits of piezoelectric elements, in a second embodiment of thepresent invention;

FIG. 8 is a block diagram illustrating the configuration of a controlcircuit for controlling piezoelectric elements;

FIGS. 9A and 9B are flowcharts illustrating operation relating tocontrol of vibration of an optical member of a camera controller;

FIG. 10 is a diagram illustrating a change in output voltage of adetection circuit with respect to driving frequency;

FIG. 11 is a diagram illustrating the output of a detection circuit in acase where a driving circuit has developed an abnormality;

FIG. 12 is a diagram illustrating a detection signal when a drivingcircuit on one side is actuated and the vibrating state of an opticalmember is detected by a detecting piezoelectric element and detectioncircuit on the opposite side;

FIG. 13 is a diagram illustrating an example of an abnormal signal;

FIG. 14 is a diagram illustrating a change in output voltage of adetection circuit with respect to driving frequency;

FIG. 15 is a diagram illustrating the output of a detection circuit in acase where a driving circuit has developed an abnormality;

FIG. 16 is a diagram illustrating a detection signal when a drivingcircuit on one side is actuated and the vibrating state of an opticalmember is detected by a detecting piezoelectric element and detectioncircuit on the opposite side;

FIG. 17 is a diagram illustrating an example of an abnormal signal;

FIG. 18 is an exploded perspective view illustrating schematically thestructure within a camera for the purpose of describing the peripheralstructure of an image capturing unit;

FIG. 19 is an exploded perspective view illustrating the structure ofthe image capturing unit; and

FIG. 20 is a sectional view taken along line A-A of FIG. 18.

DESCRIPTION OF THE EMBODIMENTS

A single-lens reflex digital camera equipped with a vibrating deviceusing piezoelectric elements according to embodiments of the presentinvention will be described in detail with reference to the drawings.

First Embodiment

FIG. 1 is a block diagram of a single-lens reflex digital cameraaccording to a first embodiment of the present invention.

In FIG. 1, an interchangeable shooting lens unit 1 forms the image of asubject. An aperture stop 111 for adjusting the amount of light thatimpinges upon an image sensor 2 is provided in the shooting lens unit 1.The image sensor 2 opto-electronically converts the image of thesubject. An optical member 4 that functions also as a dust-proof filterreferred to as a low-pass filter or cover filter is placed in front ofthe image sensor 2 in close proximity thereto. A foreign substance mayattach itself to the surface of the optical member 4. The adheringforeign substance shows up as a shadow in the image of the subject onthe image sensor 2. Piezoelectric elements 5 and 6 for vibrating theoptical member 4 to thereby remove the adhering foreign substance areplaced respectively at the left and right of the optical member 4(indicated at positions above and be low the optical member 4 in FIG. 1for the sake of convenience). A piezoelectric-element driving unit 122for vibrating the piezoelectric elements 5 and 6 independently areconnected to the piezoelectric elements 5 and 6.

An A/D converter 132 converts an analog image signal, which is outputfrom the image sensor 2, to a digital signal. An image processingapparatus 140 processes the digital image signal that is output from theA/D converter 132. A lens controller 133 controls lens position and thedegree to which the aperture stop in the shooting lens unit 1 opens.Various sensors 121, such as AF (auto focus) sensor and AE (autoexposure) sensor, are provided. A camera controller 130 controls theoverall operation of the digital camera. Also provided are an I/O unit150 such as a shutter button, display and shooting-mode selection dial,and a memory 134 for storing shot images and various information.

An operation performed by the user is acquired via the I/O unit 150.Operations that can be performed by the user include power source ON/OFFand a shooting operation, etc. If the shooting operation has beendesignated, the camera controller 130 decides appropriate shootingconditions based upon information obtained from the various sensors 121and image sensor 2, and sets an appropriate lens position, etc., via thelens controller 133. After the output signal from the image sensor 2 isdigitally converted via the A/D converter 132 following exposure, thedigital signal is subjected to appropriate image processing by the imageprocessing apparatus 140 and the processed signal is stored in thememory 134. If necessary, the image is displayed on a display unit (notshown) via the I/O unit 150.

The image processing apparatus 140 executes processing such as a whitebalance adjustment, RGB development and compressive encoding.

FIG. 2 is a diagram illustrating the external appearance of thesingle-lens reflex digital camera of the first embodiment. Specifically,FIG. 2 is a perspective view as seen from the front side of the cameraand illustrates a state in which the shooting lens unit has beendetached.

As shown in FIG. 2, the camera has a main body 100 provided with a gripportion 100 a projecting toward the front in such a manner that the usermay readily grasp the camera stably when a picture is taken. A mountportion 202 allows the detachable shooting lens unit 1 (see FIG. 1) tobe fixed to the camera main body. Mount contacts 221 have a function forexchanging a control signal, status signal and data signal, etc.,between the camera main body 100 and shooting lens unit 1, and forsupplying power to the side of the shooting lens unit. Further, themount contacts 221 may be adapted to enable optical communication andaudio communication and not just electrical communication.

A lens unlock button 204 is pressed when the shooting lens unit 1 isdetached. A mirror box 205 is placed inside the camera case. Light raysresulting from the shot are introduced into the mirror box 205 throughthe shooting lens. A quick-return mirror 206 is placed within the mirrorbox 205. The quick-return mirror 206 can take on two states, namely astate in which the quick-return mirror 206 is held at a 45° angle withrespect to the shooting optic axis in order to guide the light rays inthe direction of a pentagonal prism (not shown), and a state in whichthe quick-return mirror 206 is held at a position retracted from thelight rays in order that the light rays are guided in the direction ofthe image sensor 2 (see FIG. 1).

A shutter button 207 serving as a start switch to begin shooting, a mainoperation dial 208 for setting shutter speed and f-stop value inaccordance with the operating mode at the time of photography, and ashooting system operating-mode setting button 210 are placed on the gripside of the camera on the upper portion thereof. A portion of theresults of the operation of these operating members is displayed on anLCD display panel 209. The I/O unit 150 shown in FIG. 1 mainly includesthese operating members and the display panel, etc.

The shutter button 207 turns on a switch SW1 by being pressed through afirst stroke (half way) and turns on a switch S2 by being pressedthrough a second stroke (all the way).

The operating-mode setting button 210 sets whether multiple frames areto be shot continuously or only one frame by a single depression of theshutter button 207, and sets a self-photography mode, etc. The state setis displayed on the LCD display panel 209.

A pop-up flash unit 211, flash-mounting shoe groove 212 and flashcontact 213 are placed on the camera main body at the center of the topportion thereof. A shooting-mode setting dial 214 is placed on the upperportion of the camera near the right side thereof. The shooting-modesetting dial 214 serves also as a portion for starting an operation forremoving a foreign substance such as dust, which has attached itself tothe surface of the optical member 4, by vibrating the optical member 4using the piezoelectric elements 5 and 6.

An openable and closable external terminal cover 215 is provided on theside surface of the camera opposite the grip side. A video-signal outputjack 216 and a USB-output jack 217 serving as external interfaces arehoused in the interior accessible by opening the external terminal cover215.

FIG. 3 is an enlarged view, as seen from above, of the vicinity of animage sensor shown in FIG. 1.

Shown in FIG. 3 are the shooting lens 1, the image sensor 2 foropto-electronically converting light that has entered from the shootinglens 1, and an image sensor package 3 for installing the image sensor 2in the camera. The optical member 4, which is placed in front of theimage sensor package 3, functions also as a dust-proof filter forpreventing a foreign substance such as dust from attaching itself to thesurface of the image sensor package 3 and to the image sensor 2.Specifically, the optical member 4 comprises an optical low-pass filteror infrared-blocking filter. The driving piezoelectric elements (firstand second piezoelectric elements) 5 and 6 vibrate the optical member 4,and holding members 21 and 22 are for holding the optical member 4 in ahermetically sealed state with respect to the image sensor package 3.The details of the arrangement involving the holding members 21, 22 willbe described later with reference to FIG. 19.

FIG. 4 is a diagram illustrating a portion of the optical member 4 inFIG. 3 as seen from the side of the image sensor 2, as well asperipheral circuits of piezoelectric elements (namely circuitry withinthe piezoelectric-element driving unit 122 shown in FIG. 1).

As shown in FIG. 4, the piezoelectric elements (driving piezoelectricelements) 5 and 6 are affixed to respective ones of both ends of theoptical member 4 so as to embrace the optical member 4 between them.Detecting piezoelectric elements (first and second detectingpiezoelectric elements) 7 and 8 are placed adjacent to the piezoelectricelements 5 and 6, respectively, for detecting the state of vibration ofthe optical member 4.

A driving circuit (first driving means) 9 is for driving thepiezoelectric element 5, and a driving circuit (second driving means) 10is for driving the piezoelectric element 6. A detection circuit 11 isfor detecting a signal from the detecting piezoelectric element 7, and adetection circuit 12 is for detecting a signal from the detectingpiezoelectric element 8.

The piezoelectric elements 5 and 6 affixed to both ends of the opticalmember 4 are vibrated at a prescribed frequency, whereby the opticalmember 4 is vibrated due to the generation of standing waves and aforeign substance such as dust adhering to the surface of the opticalmember 4 is shaken off. The amplitude of vibration produced in theoptical member 4 is detected by the detecting piezoelectric elements 7and 8.

FIG. 5 is a block diagram illustrating the configuration of a controlcircuit for controlling the piezoelectric elements 5, 6 and detectingpiezoelectric elements 7, 8. Reference numerals 4, 5, 6, 7, 8, 9, 10, 11and 12 denote the components already described in conjunction with FIG.4.

The camera controller 130 controls the overall operation of the digitalcamera, as shown in FIG. 1, and also controls the vibration of thepiezoelectric elements 5, 6. An oscillating circuit 14 is controlled bythe camera controller 130 and outputs a high-frequency signal forcontrolling the piezoelectric elements 5, 6. The oscillating circuit 14outputs a vibrating signal by changing the oscillation frequency inaccordance with a control value from the camera controller 130. Apower-source circuit 15 supplies power for driving the piezoelectricelements 5, 6 and is connected to the driving circuits 9, 10.

The overall operation of the drive control circuit illustrated in FIGS.4 and 5 will now be described.

The camera controller 130 outputs a control signal to instruct theoscillating circuit 14 of the frequency necessary in order to drive thepiezoelectric elements 5 and 6. The oscillating circuit 14 outputs asignal having the frequency thus instructed and applies this signal tothe driving circuits 9 and 10. The driving circuits 9 and 10 have afunction for outputting the power, which is supplied from thepower-source circuit 15, in accordance with signals that enter from thecamera controller 130 and oscillating circuit 14 by an H-bridge circuit.

Further, the camera controller 130 is capable of individuallycontrolling whether or not outputs are delivered from the drivingcircuits 9 and 10 by outputting a drive allow/inhibit signal thatinstructs the driving circuits 9 and 10 as to whether the driving of thepiezoelectric elements is allowed or inhibited.

If outputs from the driving circuits 9 and 10 are allowed by the cameracontroller 130, then driving signals of the frequency designated by thecamera controller 130 are applied to the piezoelectric elements 5 and 6to thereby vibrate the optical member 4 and produce standing waves onthe optical member 4. It should be noted that by varying the signal thatis sent to the oscillating circuit 14, the camera controller 130 canchange the oscillation frequency of the oscillating circuit 14 and thuschange the frequency of the signals applied to the piezoelectricelements. By thus changing frequency, the number of loops or nodes ofthe standing wave on the optical member 4 can be changed and a standingwave having the largest amplitude can be produced.

When the standing wave is produced on the optical member 4, thedetecting piezoelectric elements 7 and 8 vibrate and produce signals.The signal produced by the detecting piezoelectric element 7 isconverted by the detection circuit 11 to a signal that can be detectedby the camera controller 130. The resultant signal is applied to an A/Dconversion input of the camera controller 130. Similarly, the signalproduced by the detecting piezoelectric element 8 is converted by thedetection circuit 12 to a signal that can be detected by the cameracontroller 130. The resultant signal is applied to an A/D conversioninput of the camera controller 130.

As a result, while varying the driving frequency, the camera controller130 is capable of monitoring the state of the amplitude of the standingwave generated on the optical member 4.

FIGS. 6A and 6B are flowcharts illustrating operation related to controlof the vibration of the optical member 4 by the camera controller 130.In FIG. 6A, the camera controller 130 starts operation from step S101,and the operation is either an operation for shaking a foreign substanceoff the optical member 4 or an operation for conducting a test of theforeign-substance removal system that includes the driving circuits andoptical member 4.

At step S101, the oscillating circuit 14 is instructed of theoscillation frequency, whereby the initial setting of frequency fordriving the piezoelectric elements 5, 6 is performed. Control thenproceeds to step S102.

At step S102, the camera controller 130 determines whether the presentdriving operation is test driving or driving for removal of a foreignsubstance. Control proceeds to step S112 if this is test driving or tostep S103 if this is driving for removal of a foreign substance.

At step S103, it is necessary to maximize the vibration of the opticalmember 4 since this is an operation (third control) for driving theoptical member 4 to remove a foreign substance. Therefore, in order todrive both of the piezoelectric elements 5 and 6 affixed to therespective ends of the optical member 4, the signal for allowing driveis output to both of the driving circuits 9 and 10, thereby starting thedriving of the piezoelectric elements 5 and 6. Control then proceeds tostep S104.

At step S104, the vibration of the optical member 4 is detected tomonitor the state of vibration. To accomplish this, the signals from thedetection circuits 11 and 12 are converted to digital signals by an A/Dconverter incorporated in the camera controller 130, and these signalsare monitored. Control then proceeds to step S105.

At step S105, the camera controller 130 determines whether the outputsignals from the detection circuit 11 and detection circuit 12 are equalto or greater than respective reference values. If both signals areequal to or greater than the reference values, then the cameracontroller 130 determines that they are normal and control proceeds tostep S106. If even one of the two output signals is less than thereference value, then the camera controller 130 determines that theoutput signal is abnormal and control proceeds to step S110.

At step S106, the camera controller 130 determines whether a prescribedperiod of time has elapsed since the start of driving at the setfrequency. Control proceeds to step S107 if the prescribed time periodhas elapsed. Otherwise, control returns to step S104, driving at thesame frequency is continued and the detection of the vibratory state iscontinued as well.

At step S107, the camera controller 130 instructs the oscillatingcircuit 14 to change the frequency, thereby changing the frequency atwhich the piezoelectric elements 5 and 6 are driven. Control thenproceeds to step S108. When the frequency is changed, the change is to afrequency slightly lower than the set previously.

At step S108, the camera controller 130 determines whether the frequencyset at step S107 has exceeded a prescribed range of change in frequency.If the change of frequency within the prescribed range of change infrequency has been completed, control proceeds to step S109. If it hasnot been completed, then control returns to step S104.

At step S109, the camera controller 130 inhibits driving of the drivingcircuits 9 and 10 and terminates driving for the purpose of removing theforeign substance.

At step S110, the camera controller 130 places the driving circuits 9and 10 in the driving-inhibited state since it has been found at stepS105 that one or both of the outputs of detection circuits 11 and 12 isabnormal. Control then proceeds to step S111.

At step S111, the camera controller 130 records the abnormal statedetected thus far, presents a display indicative of normality on thedisplay unit (not shown) and advances control to step S109 to terminatedriving.

The abnormality detected here is one in a case where the piezoelectricelements at both ends of the optical member 4 are driven in order toremove a foreign substance; it is presumed that the abnormality is inthe driving circuits, detection circuits, piezoelectric elements ordetecting piezoelectric elements, etc.

Next, step S112 is one at which driving for test purposes is carriedout. Here one of the piezoelectric elements of the two fixedpiezoelectric elements affixed to the ends of the optical member 4 isdriven. The camera controller 130 then detects the state of vibrationusing the detecting piezoelectric elements at both ends and determineswhether there is any abnormality. The camera controller 130 thereforesets the driving circuit 9 to allow drive, inhibits the driving of thedriving circuit 10 and drives only the piezoelectric element 5. Controlthen proceeds to step S113.

At step S113, in order to detect vibration of the optical member 4 andmonitor its state of vibration, the camera controller 130 converts thesignals from the detection circuits 11 and 12 to digital signals byusing the A/D converter incorporated in the camera controller 130, andmonitors these digital signals. Control then proceeds to step S114.

At step S114, the camera controller 130 determines whether the outputsignal from the detection circuit 11 is equal to or greater than areference value. If the signal is equal to or greater than the referencevalue, then the camera controller 130 determines that the signal isnormal and control proceeds to step S115. If the output signal is lessthan the reference value, then the camera controller 130 determines thatthe output signal is abnormal and control proceeds to step S122.

At step S115, the camera controller 130 determines whether the outputsignal from the detection circuit 12 is equal to or greater than areference value. If the signal is greater equal to or than the referencevalue, then the camera controller 130 determines that the signal isnormal and control proceeds to step S116. If the output signal is lessthan the reference value, then the camera controller 130 determines thatthe output signal is abnormal and control proceeds to step S120.

At step S116, the camera controller 130 places the driving circuit 10 inthe driving-allowed state and places the driving circuit 9 in thedriving-inhibited state in order to drive the piezoelectric element onthe side opposite the piezoelectric element driven at step S112. Thecamera controller 130 then drives only the piezoelectric element 6 andadvances control to step S117.

At step S117, the vibration of the optical member 4 is detected tomonitor the state of vibration. Accordingly, the signals from thedetection circuits 11 and 12 are converted to digital signals by the A/Dconverter built in the camera controller 130, and these signals aremonitored. Control then proceeds to step S118.

At step S118, the camera controller 130 determines whether the output ofthe detection circuit 12 is equal to or greater than the referencevalue. If the signal is equal to or greater than the reference value,then the camera controller 130 determines that the signal is normal andadvances control to step S119. If the signal is less than the referencevalue, then the camera controller 130 determines that the output signalis abnormal is advances control to step S122.

At step S119, the camera controller 130 determines whether the output ofthe detection circuit 11 is equal to or greater than the referencevalue. If the signal is equal to or greater than the reference value,then the camera controller 130 determines that the signal is normal andadvances control to step S109 to terminate driving. If the signal isless than the reference value, then the camera controller 130 determinesthat the output signal is abnormal and advances control to step S120.

At step S120, the camera controller 130 decides that the optical member4 is abnormal (first control) because the output from the detectingpiezoelectric element attached to the same side as that of thepiezoelectric element that was actually driven is normal whereas theoutput from the detecting piezoelectric element attached to the oppositeside of the optical member 4 is abnormal. Control then proceeds to stepS121.

Since it has been decided at step S120 that the optical member 4 isabnormal, there is the possibility that the optical member 4 has splitand a possibility that a correct image will not be shot. At step S121,therefore, the camera controller 130 executes processing to inhibit asubsequent shooting operation and records the fact of the abnormal statein a memory or the like, not shown. Further, the camera controller 130causes an external display unit (not shown) to display the fact that theshooting optical system is abnormal and cannot take a picture. Controlthen proceeds to step S109, where the test driving operation isterminated.

Next, since the output from the detecting piezoelectric element attachedto the same side as that of the piezoelectric element that was actuallydriven is abnormal, it may be construed that there is a high likelihoodthat the piezoelectric element itself is not vibrating (second control).Consequently, although the operation for removing the foreign substancecannot be performed normally, it is construed that there is no problemin the shooting optical system, unlike the case where control proceededto step S120. At step S122, therefore, it is decided that it is possibleto shoot a picture. Furthermore, the fact that drive for removal offoreign substance is abnormal is recorded in a memory or the like, notshown. Driving for removal of the foreign substance is inhibited at thistime. Further, the fact that shooting is possible but not the operationfor removing a foreign substance is displayed on the external displayunit (not shown). Control then proceeds to step S109 and the driving fortest purposes is terminated.

A concrete example of a detection signal used at step S105 will bedescribed with reference to FIG. 10.

As shown in FIG. 10, a horizontal axis 1201 indicates driving frequency,and a vertical axis 1202 indicates the output voltage of the detectioncircuits 11, 12. A change in the output voltage of the detectioncircuits 11, 12 with respect to driving frequency is indicated at 1203.The change at 1203 indicates how the output voltage of the detectioncircuits 11, 12 varies with a change in driving frequency. The waveformchanges depending upon the vibratory state of the optical member 4.

The level of the evaluation reference value mentioned at step S105 isindicated at 1204. If the output of the detection circuit 11 or 12 isequal to or greater than this evaluation level, then it is decided thatthe output is normal. If the output is less than the evaluation level,then it is decided that the output is abnormal.

FIG. 11 indicates a case where an abnormality has developed in thedriving circuits 9, 10. FIG. 11 illustrates a state in which the outputvoltage of the detection circuits 11, 12 it at a level below theevaluation level 1204, as indicated at 1205.

Step S118 is the step at which abnormality of the driving circuit 10 isjudged. Abnormality detection can be performed in a manner similar tothe case of step S105 (FIGS. 10 and 11) based upon the output voltage ofthe detection circuit 12.

A concrete example of a detection signal used at step S119 will bedescribed next.

Reference numeral 1206 in FIG. 12 indicates the detection signal fromthe detection circuit 11 when only the driving circuit 10 is actuated,only the piezoelectric element 6 is driven and the state of vibration ofoptical member 4 is detected by the detecting piezoelectric element 7and detection circuit 11. Since the detection signal is a signalindicating the state of vibration of the optical member 4, there aremany cases where the output level falls below that of the signal at stepS118. Consequently, an evaluation level indicated at 1207 is a valuelower than the evaluation level at step S118.

Reference numeral 1208 in FIG. 13 shows an example of an abnormal signaland indicates a case where the vibration of the optical member 4 issmaller than the prescribed amplitude for some reason. In this case, thedetection signal from the detection circuit 11 also has a low value and,hence, abnormality is detected. Further, in a case such as one in whichthe optical member 4 is damaged, the detection signal will besubstantially “0” and, hence, abnormality can be detected.

Thus, in order to detect abnormality in a driving circuit, vibration isdetected by a detecting piezoelectric element placed in close proximityto a driving piezoelectric element. Further, in order to detectabnormality of vibration inclusive of that of the optical element,vibration is detected and abnormality judged by a detectingpiezoelectric element placed at a position opposing a drivingpiezoelectric element with the optical element interposed therebetween.

Thus, in the first embodiment, as described above, detectingpiezoelectric elements are provided in close proximity to piezoelectricelements placed at respective ones of both ends of an optical member,the piezoelectric element on one side is driven and vibration isdetected by the detecting piezoelectric element on the opposite side ofthe optical member. As a result, the state of vibration of the opticalmember can be detected and it is possible to detect abnormality of theoptical member and abnormality in the driving system of thepiezoelectric elements.

Second Embodiment

In the second embodiment, the configuration of the digital camera is thesame as that of the first embodiment illustrated in FIGS. 1 and 2 andneed not be described again. Further, the arrangement in the vicinity ofthe image sensor as seen from above is the same as that of the firstembodiment shown in FIG. 3 and need not be described again.

FIG. 7 is a diagram illustrating a portion of the optical member 4 inFIG. 3 as seen from the side of the image sensor 2, as well asperipheral circuits of piezoelectric elements (namely circuitry withinthe piezoelectric-element driving unit 122 shown in FIG. 1). Structuralelements in FIG. 7 identical with those of FIG. 4 illustrating the firstembodiment are designated by like reference characters.

As shown in FIG. 7, the piezoelectric elements 5 and 6 are affixed torespective ones of both ends of the optical member 4.

Driving circuit 9 is for driving the piezoelectric element 5, anddriving circuit 10 is for driving the piezoelectric element 6. Adetection circuit (first detection means) 111 is connected to thedriving signal of the piezoelectric element 5, detects the drivingsignal when the piezoelectric element is driven and detects the signalfrom the piezoelectric element 5 when the piezoelectric element is notdriven. A detection circuit (second detection means) 112 is connected tothe driving signal of the piezoelectric element 6, detects the drivingsignal when the piezoelectric element is driven and detects the signalfrom the piezoelectric element 6 when the piezoelectric element is notdriven.

The piezoelectric elements 5 and 6 affixed to both ends of the opticalmember 4 are vibrated at a prescribed frequency, whereby the opticalmember 4 is vibrated due to the generation of standing waves and aforeign substance such as dust adhering to the surface of the opticalmember 4 is shaken off. The detection circuits 111 and 112 monitor thedriving signals during the driving of the piezoelectric elements anddetect the state of vibration of the optical member 4 during the timethat the piezoelectric elements are not being driven.

FIG. 8 is a block diagram illustrating the configuration of a controlcircuit for controlling the piezoelectric elements 5, 6. Structuralelements in FIG. 8 identical with those in FIG. 5 illustrating the firstembodiment are designated by like reference characters.

Camera controller 130 controls the overall operation of the digitalcamera, as shown in FIG. 1, and also controls the vibration of thepiezoelectric elements 5, 6. Oscillating circuit 14 is controlled by thecamera controller 130 and outputs a high-frequency signal forcontrolling the piezoelectric elements 5, 6. The oscillating circuit 14outputs a vibrating signal by changing the oscillation frequency inaccordance with a control value from the camera controller 130.Power-source circuit 15 supplies power for driving the piezoelectricelements 5, 6 and is connected to the driving circuits 9, 10.

The overall operation of the drive control circuit illustrated in FIGS.7 and 8 will now be described.

The camera controller 130 outputs a control signal to instruct theoscillating circuit 14 of the frequency necessary in order to drive thepiezoelectric elements 5 and 6. The oscillating circuit 14 outputs asignal having the frequency thus instructed and applies this signal tothe driving circuits 9 and 10. The driving circuits 9 and 10 have afunction for outputting the power, which is supplied from thepower-source circuit 15, in accordance with signals that enter from thecamera controller 130 and oscillating circuit 14 by an H-bridge circuit.

Further, the camera controller 130 is capable of individuallycontrolling whether or not outputs are delivered from the drivingcircuits 9 and 10 by outputting a drive allow/inhibit signal thatinstructs the driving circuits 9 and 10 as to whether the driving of thepiezoelectric elements is allowed or inhibited.

If outputs from the driving circuits 9 and 10 are allowed by the cameracontroller 130, then driving signals of the frequency designated by thecamera controller 130 are applied to the piezoelectric elements 5 and 6to thereby vibrate the optical member 4 and produce standing waves onthe optical member 4. It should be noted that by varying the signal thatis sent to the oscillating circuit 14, the camera controller 130 canchange the oscillation frequency of the oscillating circuit 14 and thuschange the frequency of the signals applied to the piezoelectricelements. By thus changing frequency, the number of loops or nodes ofthe standing wave on the optical member 4 can be changed and a standingwave having the largest amplitude can be produced.

When the piezoelectric elements 5 and 6 are driven, the driving signalsof the piezoelectric elements 5 and 6 are detected by the detectioncircuits 111 and 112, these detection signals are converted to digitalsignals by the A/D converter inside the camera controller 130 and thestates of the signals are detected. Further, with regard to thepiezoelectric elements affixed to respective ones of both ends of theoptical member 4, by driving the piezoelectric element on one side andnot driving the piezoelectric element on the other side, the standingwaves on the optical member 4 produced by driving the piezoelectricelement on the one side are detected by the piezoelectric element on theopposite side.

For example, in a case where the piezoelectric element 5 is driven, thesignal produced by the piezoelectric element 6 is converted by thedetection circuit 112 to a signal that can be detected by the cameracontroller 130. The resultant signal is applied to an A/D conversioninput of the camera controller 130.

As a result, the camera controller 130 is capable of monitoring thestates of the driving circuits 9 and 10 and can also monitor theamplitude of the standing waves produced in the optical member 4 whileit varies the driving frequency.

FIGS. 9A and 9B are flowcharts illustrating operation related to controlof the vibration of the optical member 4 by the camera controller 130.In FIG. 9A, the camera controller 130 starts operation from step S201,and the operation is either an operation for shaking a foreign substanceoff the optical member 4 or an operation for conducting a test of theforeign-substance removal system that includes the driving circuits andoptical member 4.

At step S201, the oscillating circuit 14 is instructed of theoscillation frequency, whereby the initial setting of frequency fordriving the piezoelectric elements 5, 6 is performed. Control thenproceeds to step S202.

At step S202, the camera controller 130 determines whether the presentdriving operation is test driving or driving for removal of a foreignsubstance. Control proceeds to step S212 if this is test driving or tostep S203 if this is driving for removal of a foreign substance.

At step S203, it is necessary to maximize the vibration of the opticalmember 4 since this is an operation for driving the optical member 4 toremove a foreign substance. Therefore, in order to drive both of thepiezoelectric elements 5 and 6 affixed to the respective ends of theoptical member 4, the signal for allowing drive is output to both of thedriving circuits 9 and 10, thereby starting the driving of thepiezoelectric elements 5 and 6. Control then proceeds to step S204.

At step S204, the driving signals of the driving circuits 9 and 10 (thestate of vibration of the optical member 4) are monitored. In order toaccomplish this, the signals from the detection circuits 111 and 112 areconverted to digital signals by the A/D converter inside the cameracontroller 130, and these signals are monitored. Control then proceedsto step S205.

At step S205, the camera controller 130 determines whether the outputsignals from the detection circuit 111 and detection circuit 112 areequal to or greater than respective reference values. If both signalsare equal to or greater than the reference values, then the cameracontroller 130 determines that they are normal and control proceeds tostep S206. If even one of the two output signals is less than thereference value, then the camera controller 130 determines that theoutput signal is abnormal and control proceeds to step S210.

At step S206, the camera controller 130 determines whether a prescribedperiod of time has elapsed since the start of driving at the setfrequency. Control proceeds to step S207 if the prescribed time periodhas elapsed. Otherwise, control returns to step S204, driving at thesame frequency is continued and the detection of the vibratory state iscontinued as well.

At step S207, the camera controller 130 instructs the oscillatingcircuit 14 to change the frequency, thereby changing the frequency atwhich the piezoelectric elements 5 and 6 are driven. Control thenproceeds to step S208. When the frequency is changed, the change is to afrequency slightly lower than the set previously.

At step S208, the camera controller 130 determines whether the frequencyset at step S207 has exceeded a prescribed range of change in frequency.If the change of frequency within the prescribed range of change infrequency has been completed, control proceeds to step S209. If it hasnot been completed, then control returns to step S204.

At step S209, the camera controller 130 inhibits driving of the drivingcircuits 9 and 10 and terminates driving for the purpose of removing theforeign substance.

At step S210, the camera controller 130 places the driving circuits 9and 10 in the driving-inhibited state since it has been found at stepS205 that one or both of the outputs of detection circuits 11 and 12 isabnormal. Control then proceeds to step S111.

At step S211, the camera controller 130 records the abnormal statedetected thus far, presents a display indicative of normality on thedisplay unit (not shown) and advances control to step S209 to terminatedriving.

The abnormality detected here is one in a case where the piezoelectricelements at both ends of the optical member 4 are driven in order toremove a foreign substance; it is presumed that the abnormality is inthe driving circuits, detection circuits, piezoelectric elements ordetecting piezoelectric elements, etc.

Next, step S212 is one at which driving for test purposes is carriedout. Here one of the piezoelectric elements of the two fixedpiezoelectric elements affixed to the ends of the optical member 4 isdriven. The camera controller 130 then detects the state of vibrationusing the detecting piezoelectric elements at both ends and determineswhether there is any abnormality. The camera controller 130 thereforesets the driving circuit 9 to allow drive, inhibits the driving of thedriving circuit 10 and drives only the piezoelectric element 5. Controlthen proceeds to step S213.

At step S213, in order to monitor the signal that drives thepiezoelectric element 5, detect vibration of the optical member 4 by thepiezoelectric element 6 and monitor its state of vibration, the signalsfrom the detection circuits 111 and 112 are input to the cameracontroller 130. These signals, which are input to the A/D converterinside the camera controller 130, are converted to digital signalsthereby and the digital signals are monitored by the camera controller130. Control then proceeds to step S214.

At step S214, the camera controller 130 determines whether the outputsignal from the detection circuit 111 is equal to or greater than areference value. If the signal is equal to or greater than the referencevalue, then the camera controller 130 determines that the signal isnormal and control proceeds to step S215. If the output signal is lessthan the reference value, then the camera controller 130 determines thatthe output signal is abnormal and control proceeds to step S222.

At step S215, the camera controller 130 determines whether the outputsignal from the detection circuit 112 is equal to or greater than areference value. If the signal is equal to or greater than the referencevalue, then the camera controller 130 determines that the signal isnormal and control proceeds to step S216. If the output signal is lessthan the reference value, then the camera controller 130 determines thatthe output signal is abnormal and control proceeds to step S220.

At step S216, the camera controller 130 places the driving circuit 10 inthe driving-allowed state and places the driving circuit 9 in thedriving-inhibited state in order to drive the piezoelectric element onthe side opposite the piezoelectric element driven at step S212. Thecamera controller 130 then drives only the piezoelectric element 6 andadvances control to step S217.

At step S217, in order to monitor the signal that drives thepiezoelectric element 6, detect vibration of the optical member 4 by thepiezoelectric element 5 and monitor its state of vibration, the signalsfrom the detection circuits 111 and 112 are input to the cameracontroller 130. These signals, which are input to the A/D converterinside the camera controller 130, are converted to digital signalsthereby and the digital signals are monitored by the camera controller130. Control then proceeds to step S218.

At step S218, the camera controller 130 determines whether the outputsignal from the detection circuit 112 is equal to or greater than areference value. If the signal is equal to or greater than the referencevalue, then the camera controller 130 determines that the signal isnormal and control proceeds to step S219. If the output signal is lessthan the reference value, then the camera controller 130 determines thatthe output signal is abnormal and control proceeds to step S222.

At step S219, the camera controller 130 determines whether the outputsignal from the detection circuit 111 is equal to or greater than areference value. If the signal is greater equal to or than the referencevalue, then the camera controller 130 determines that the signal isnormal and advances control to step S209 to terminate driving. If thesignal is less than the reference value, then the camera controller 130determines that the output signal is abnormal and advances control tostep S120.

At step S220, the camera controller 130 decides that the optical member4 is abnormal because the driving signal applied to the piezoelectricelement that was actually driven is normal whereas the output from thepiezoelectric element attached to the opposite side of the opticalmember 4 is abnormal. Control then proceeds to step S221.

Since it has been decided at step S220 that the optical member 4 isabnormal, there is the possibility that the optical member 4 has splitand a possibility that a correct image will not be shot. At step S221,therefore, the camera controller 130 executes processing to inhibit asubsequent shooting operation and records the fact of the abnormal statein a memory or the like, not shown. Further, the camera controller 130causes an external display unit (not shown) to display the fact that theshooting optical system is abnormal and cannot take a picture. Controlthen proceeds to step S209, where the test driving operation isterminated.

Next, since the driving signal applied to piezoelectric element that wasactually driven is abnormal, it may be construed that there is anabnormality in the driving circuits, detection circuits or piezoelectricelements, etc. Consequently, although the operation for removing theforeign substance cannot be performed normally, it is construed thatthere is no problem in the shooting optical system, unlike the casewhere control proceeded to step S220. At step S222, therefore, it isdecided that it is possible to shoot a picture. Furthermore, the factthat drive for removal of foreign substance is abnormal is recorded in amemory or the like, not shown. Driving for removal of the foreignsubstance is inhibited at this time. Further, the fact that shooting ispossible but not the operation for removing a foreign substance isdisplayed on the external display unit (not shown). Control thenproceeds to step S209 and the driving for test purposes is terminated.

A concrete example of a detection signal used at step S205 will bedescribed with reference to FIG. 14.

As shown in FIG. 14, a horizontal axis 1301 indicates driving frequency,and a vertical axis 1302 indicates the output voltage of the detectioncircuits 111, 112. A change in the output voltage of the detectioncircuits 111, 112 with respect to driving frequency is indicated at1303. The change at 1303 indicates how the output voltage of thedetection circuits 111, 112 varies with a change in driving frequency.The waveform changes depending upon the vibratory state of the opticalmember 4. In a case where the driving signals are being output from thedriving circuits 9 and 10, the detection circuits 111 and 112 detect theoutput signals of the driving circuits 9 and 10, respectively, andtherefore output constant voltages irrespective of the drivingfrequency.

The level of the evaluation reference value mentioned at step S205 isindicated at 1304. If the output of the detection circuit 111 or 112 isequal to or greater than this evaluation level, then it is decided thatthe output is normal. If the output is less than the evaluation level,then it is decided that the output is abnormal.

FIG. 15 indicates a case where an abnormality has developed in thedriving circuits 9, 10. FIG. 15 illustrates a state in which the outputvoltage of the detection circuits 111, 112 it at a level below theevaluation level 1304, as indicated at 1305.

Step S218 is the step at which abnormality of the driving circuit 10 isjudged. Abnormality detection can be performed in a manner similar tothe case of step S205 (FIGS. 14 and 15) based upon the output voltage ofthe detection circuit 112.

A concrete example of a detection signal used at step S219 will bedescribed next.

Reference numeral 1306 in FIG. 16 indicates the detection signal fromthe detection circuit 111 when only the driving circuit 10 is actuated,only the piezoelectric element 6 is driven and the state of vibration ofoptical member 4 is detected by the detecting piezoelectric element 5and detection circuit 111. Since the detection signal is a signalindicating the state of vibration of the optical member 4, there aremany cases where the output level falls below that of the signal at stepS218. Consequently, an evaluation level indicated at 1307 is a valuelower than the evaluation level at step S218.

Reference numeral 1308 in FIG. 17 shows an example of an abnormal signaland indicates a case where the vibration of the optical member 4 issmaller than the prescribed amplitude for some reason. In this case, thedetection signal from the detection circuit 111 also has a low valueand, hence, abnormality is detected. Further, in a case such as one inwhich the optical member 4 is damaged, the detection signal will besubstantially “0” and, hence, abnormality can be detected.

Thus, in order to detect abnormality in a driving signal, the drivingsignal is detected. In order to detect abnormality of vibrationinclusive of that of the optical element, vibration is detected andabnormality judged by a non-driven piezoelectric element placed at aposition opposing a driving piezoelectric element with the opticalelement interposed therebetween.

Thus, in the second embodiment, as described above, a drivingpiezoelectric element is used instead of a vibration-detectingpiezoelectric element. In other words, of two piezoelectric elements,the piezoelectric element on one side is driven and the piezoelectricelement on the side not driven is used for detection. This makes itpossible to detect the state of vibration of an optical member withoutproviding a detecting piezoelectric element.

(Structure of Image Capturing Unit)

An image capturing unit 400 will be described with reference to FIGS. 18to 20. FIG. 18 is an exploded perspective view illustratingschematically the structure within a camera for the purpose ofdescribing the peripheral structure of the image capturing unit 400. Thecamera has a main-body chassis 300 serving as the frame of the cameramain body. Placed in the chassis 300 on the side facing the subject arethe mirror box 205 and a shutter unit 32 in the order mentioned startingfrom the subject side. The image capturing unit 400 is placed on theside of the chassis 300 that faces the photographer. The image capturingunit 400 is secured to the mounting face of the mount portion 202 towhich the shooting lens unit is mounted and which serves as a referenceand is adjusted in such a manner that the imaging surface of the imagesensor 2 will be spaced a prescribed distance away from and lie parallelto the mounting face.

FIG. 19 is an exploded perspective view illustrating the structure ofthe image capturing unit 400. The image capturing unit 400 generallycomprises a vibrating unit 470, a resilient member 450 and an imagesensor unit 500. Although the details will be described later, thevibrating unit 470 is secured to the image sensor unit 500 with theresilient member 450 sandwiched therebetween.

The image sensor unit 500 will be described with reference to FIGS. 19and 20. The image sensor unit 500 includes a fixing member 510 whichholds the image sensor 2 and to which a biasing member 460 of thevibrating unit 470 is secured; a circuit board 520 on which the electriccircuitry of the imaging system is mounted and which is placed on theside of the fixing member 510 that faces the photographer; a shield case530 formed by a metal having electrical conductivity; a shielding member540, which is formed to have an opening corresponding to the effectivearea of the opto-electronic converting surface of the image sensor 2,placed on the side of the fixing member 510 facing the subject; and anoptical low-pass filter holding member 550 for holding an opticallow-pass filter 410.

The fixing member 510 has positioning pin portions 510 a for positioningrelative to the biasing member 460 of the vibrating unit 470; screwholes 510 b for securing the circuit board 520 and shield case 530 byscrews; and screw holes 510 c for securing the biasing member 460(fixing portions 460 b) of the vibrating unit 470 by screws.

FIG. 20 is a sectional view taken along line A-A of FIG. 18. The surfaceof the shielding member 540 on the side facing the subject abuts againstthe optical low-pass filter 410, and the surface of the shielding member540 on the side facing the photographer abuts against a cover glass 2 aof the image sensor 2. Double-sided tape is affixed to the sides of theshielding member 540 facing the subject and facing the photographer. Theoptical low-pass filter 410 is fixed to and held on the cover glass 2 aby the doubled-sided tape on the shielding member 540. As a result, theshielding member 540 is sealed between the optical low-pass filter 410and the cover glass 2 a of the image sensor 2 and a sealed space thatprevents the intrusion of a foreign substance such as dust is thusformed. The piezoelectric element 5 is secured to the optical member(infrared-blocking filter) 4 on the side facing the image sensor 2, asillustrated.

The circuit board 520 and 530 are provided respectively with escapeholes 520 a, 530 a for screws. The circuit board 520 and shield case 530are fixedly engaged with the fixing member 510 by screws using theescape holes 520 a, 530 a for screws and the screw holes 510 b. Theshield case 530 is connected to circuit ground potential in order toprotect the electric circuit from static electricity, etc.

The optical low-pass filter holding member 550 is secured to the coverglass 2 a of the image sensor 2 by the doubled-sided tape on theshielding member 540. The optical low-pass filter 410 is positioned atthe location of an opening in the optical low-pass filter holding member550 and is fixed to and held on the shielding member 540 by thedouble-sided tape.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2007-039830, filed Feb. 20, 2007, and 2007-142330, filed May 29, 2007,which are hereby incorporated by reference herein in their entirety.

1. An image capturing apparatus comprising: an image sensor adapted toopto-electronically convert the image of a subject; an optical memberplaced in front of said image sensor; first and second piezoelectricelements placed at respective ones of both ends of said optical member;first and second driving units adapted to independently vibrate saidfirst and second piezoelectric elements, respectively; a detection unithaving first and second detecting piezoelectric elements placed adjacentto said first and second piezoelectric elements, respectively, fordetecting vibration of said optical member; and a first control unitadapted to control said first and second driving units and saiddetection unit so as to vibrate said optical member by vibrating saidfirst piezoelectric element and detect vibration of said optical memberusing said second detecting piezoelectric element, or vibrate saidoptical member by vibrating said second piezoelectric element and detectvibration of said optical member using said first detectingpiezoelectric element.
 2. The apparatus according to claim 1, furthercomprising a second control unit adapted to control said first andsecond driving units and said detection unit so as to vibrate saidoptical member by vibrating said first piezoelectric element and detectvibration of said optical member using said first detectingpiezoelectric element, or vibrate said optical member by vibrating saidsecond piezoelectric element and detect vibration of said optical memberusing said second detecting piezoelectric element; wherein operation ofsaid image capturing apparatus in a case where an abnormality has beendetected by said first control unit is made to differ from operation ina case where an abnormality has been detected by said second controlunit.
 3. The apparatus according to claim 2, wherein in a case where anabnormality has been detected by said first control unit, a shootingoperation is inhibited; and in a case where an abnormality has beendetected by said second control unit but not by said first control unit,vibration of said first and second piezoelectric elements for thepurpose of removing a foreign substance is inhibited without inhibitingthe shooting operation.
 4. The apparatus according to claim 1, furthercomprising a third control unit adapted to control said first and secondcontrol units so as to vibrate both said first and second piezoelectricelements in a case where a foreign substance that has attached itself tosaid optical member is to be removed.
 5. An image capturing apparatuscomprising: an image sensor adapted to opto-electronically convert theimage of a subject; an optical member placed in front of said imagesensor; first and second piezoelectric elements placed at respectiveones of both ends of said optical member; first and second driving unitsadapted to independently vibrate said first and second piezoelectricelements, respectively; a first detection unit connected between saidfirst piezoelectric element and said first driving unit and adapted todetect an output signal that is output from said first piezoelectricelement owing to vibration of said first piezoelectric element; a seconddetection unit connected between said second piezoelectric element andsaid second driving unit and adapted to detect an output signal that isoutput from said second piezoelectric element owing to vibration of saidsecond piezoelectric element; and a first control unit adapted tovibrate said optical member by vibrating said first piezoelectricelement and detect the output signal, which is output from said secondpiezoelectric element, using said second detection unit, or vibrate saidoptical member by vibrating said second piezoelectric element and detectthe output signal, which is output from said first piezoelectricelement, using said first detection unit.
 6. The apparatus according toclaim 5, further comprising a second control unit adapted to controlsaid first and second driving units and said detection unit so as tovibrate said optical member by vibrating said first piezoelectricelement and detect the output signal that is output from said firstpiezoelectric element using said first detection unit, or vibrate saidoptical member by vibrating said second piezoelectric element and detectthe output signal that is output from said second piezoelectric elementusing said second detection unit; wherein operation of said imagecapturing apparatus in a case where an abnormality has been detected bysaid first control unit is made to differ from operation in a case wherean abnormality has been detected by said second control unit.
 7. Theapparatus according to claim 6, wherein in a case where an abnormalityhas been detected by said first control unit, a shooting operation isinhibited; and in a case where an abnormality has been detected by saidsecond control unit but not by said first control unit, vibration ofsaid first and second piezoelectric elements for the purpose of removinga foreign substance is inhibited without inhibiting the shootingoperation.
 8. The apparatus according to claim 5, further comprising athird control unit adapted to control said first and second controlunits so as to vibrate both said first and second piezoelectric elementsin a case where a foreign substance that has attached itself to saidoptical member is to be removed.